1. Field
The present disclosure relates to an unmanned aerial vehicle (UAV) able to harvest energy from updrafts and a method of operating an unmanned aerial vehicle.
2. Background
Pilots of gliders are aware of the potential to increase range and/or glide time (endurance) by utilising updrafts of air caused by the heating of the Earth's surface. These naturally occurring upward flows of air, often referred to as thermals, form in columns and can be utilised to lift or reduce the fall of a glider passing therethrough. Gliders can even circle within an updraft to gain a desired altitude up to a theoretical maximum altitude.
UAVs can take advantage of updrafts in the same way as gliders. However, in many countries UAVs are prohibited from flying in controlled airspace and may therefore be subject to an artificial ceiling that is lower than the true theoretical maximum altitude. As such, it is not always possible for a UAV to achieve the theoretically available height gains from updrafts.
There is therefore a need to provide a UAV that can derive benefit from an updraft when prohibited from climbing above a threshold altitude.